POS0765 IS THERE ANY DIFFERENCE IN THE CLINICAL FEATURES AND OUTCOMES OF PROLIFERATIVE AND NON-PROLIFERATIVE FORMS OF LUPUS NEPHRITIS PROVEN BY BIOPSY?
Authors: E. Duran, T. Yildirim, A. Taghiyeva, E. Bilgin, M. Arici, A. Saglam, S. Özen, M. Üner, Y. Erdem, U. Kalyoncu, A. I. Ertenli
Journal: Annals of the Rheumatic Diseases (2022)

Background Lupus nephritis (LN), which occurs in 60-70% of patients with systemic lupus erythematosus, is a major determinant of morbidity and mortality. There still are many uncertain aspects in clinical, pathological, and prognostic characteristics about LN. Objectives We aimed to compare clinical features, outcomes, and to define the predictive factors of complete renal response (CRR) in patients with proliferative and non-proliferative LN. Methods Patients with SLE followed between 2014 and 2020 at Hacettepe University Hospitals and who had a kidney biopsy were the subject of the study. One hundred and sixteen patients whose kidney biopsy reported as LN were evaluated retrospectively. Clinical features, laboratory values at the time of kidney biopsy, histopathological forms of LN, and renal response (complete or partial) were recorded. The predictive factors for CRR during the two-year follow-up after induction therapy were analyzed. Results Of 116 (93 females, 23 males) patients, 95 (81.9%) were in the proliferative (class III and IV) and 21 (18.1%) were in the non-proliferative group (class II and V). In the proliferative group, elevated basal creatinine, median daily proteinuria, anti-dsDNA positivity, low C3 and C4, the presence of active urinary sediment, and median renal SLE Disease Activity Index (SLEDAI) scores at the time of kidney biopsy were significantly higher than non-proliferative group. During the two-year follow-up after LN diagnosis, 70 patients achieved CRR and time-to-CRR was similar for the groups (p=0.64, log-rank). The Cox proportional hazards model showed that achieving CRR was associated with female gender [HR: 2.15 (1.19-3.89 95% CI), p=0.011], newly diagnosed SLE with renal biopsy [2.15 (1.26-3.67), p=0.005], hypertension [0.40 (0.27-0.94), p=0.032], eGFR increase [1.01 (1.00-1.01), p=0.046], and presence of active urinary sediment [0.46 (0.22-0.96), p=0.039]. Conclusion Achieving CRR was similar in both the proliferative and non-proliferative LN patients although certain laboratory parameters differed at onset. Our results indicated the importance of kidney biopsy in the decision-making of treatment of SLE patients with renal involvement and that the defined factors associated with CRR achievement help to predict good renal response. Table 1. Demographic, clinical characteristics, and outcomes of the patients with LN Variables* All patients Proliferative LN Non-Proliferative LN p n=116 n=95 n=21 Age at SLE diagnosis, years 18.3 (16) 19.2 (15) 16 (16) 0.32 Sex, female 93 (80.2) 75 (78.9) 18 (85.7) 0.48 Age at kidney biopsy, years 21 (17.7) 22 (17) 18 (15) 0.19 Patients newly diagnosed SLE with renal biopsy 65 (56) 53 (55.8) 12 (57.1) 0.91 Follow-up time for LN, years 5.5 (8) 5.1 (8.2) 6.2 (5.1) 0.80 SLE disease duration 8 (8.7) 8.1 (9.6) 7.9 (7.3) 0.53 Hypertension 31 (26.7) 26 (27.4) 5 (23.8) 0.74 Laboratory values on the kidney biopsy Creatinine level (mg/dL) 0.7 (0.5) 0.8 (0.5) 0.56 (0.1) 0.006 Creatinine &gt; UNL 37 (32.5) 34 (36.6) 3 (14.3) 0.04 eGFR (mL/min/1.73m 2 ) 113 (54) 107 (54) 129 (45) 0.04 Albumin (g/dL) 3.3 (1.1) 3.1 (1.2) 3.5 (1) 0.09 24-hour urine protein, gr/day 2.3 (3.3) 2.4 (3.6) 0.9 (1.8) 0.03 Anti-dsDNA positivity 94 (81) 80 (87.9) 14 (70) 0.04 Low C3 and C4 levels 93 (80.2) 81 (88) 12 (57.1) 0.001 Active urinary sediment 91 (83.5) 78 (89.8) 12 (57.1) &lt;0.001 Renal SLEDAI 12 (8) 12 (8) 4 (4) &lt;0.001 During the two-year follow-up after LN diagnosis Complete renal response 70 (70.7) 56 (70.9) 14 (70) 0.99 Partial renal response 23 (23.2) 17 (21.5) 6 (30) 0.64 No response 6 (6.1) 6 (7.6) 0 NA Relapse 20 (21.5) 15 (20.5) 5 (25) 0.84 ESRD 4(4) 4 (4.2) 0 NA Death 3 (3) 3 (3.2) 0 NA * n (%), if otherwise specified; median (IQR) for numeric values ESRD: End-stage renal disease, GFR: Glomerular filtration rate, LN: Lupus nephritis, SLE: Systemic lupus erythematosus, SLEDAI: Systemic Lupus Erythematosus Disease Activity Index; UNL: Upper normal limit Figure 1. Kaplan-Meier survival curve for complete renal response (CRR) achievement during the two-year follow-up according to the kidney biopsy results Disclosure of Interests None declared